I've got an issue with one at the moment. Basically I was travelling behind a lorry carrying a load of junk, something fell off the back, bounced off the road and hit my screen. I have their details but I'm guessing its going to be more hassle than it's worth? I have glass cover on my policy so only have to pay the excess.
If the chip is not in the eye vision area in front of you, you can buy a windscreen resin kit for around a tenner.
I have had my kit for six years and still works fine, you just put a drop in the chip/crack and it hardens under the UV light of the sun (so cannot do in the garage, unless you have a UV light). Once hardened you take a razor blade (supplied with kit) and carefully trim off excess, and the resin is the same light refraction as the glass so is nearly an invisible repair.
PAINT CHIP AT FRONT OF CAR:
Its hard to avoid these chips, but my secret told by my old man is to keep well back from the car in front of you and you will avoid a lot of chipping. Though sods law you will get the occasional one from passing cars. I check my car after every wash and use a touch up paint stick.